Stored Object Replication

Abstract

The number of replicas of an object to be stored is determined, at least in part, as a function of an access control policy for that object.

1 . A method comprising:
 determining a replication number for an object at least in part as a function of an access control policy for that object; and   storing that number of replicas of said object.   
     
     
         2 . A method as recited in  claim 1  wherein said determining involves interpreting said access control policy is interpreted to determine users that are to be permitted to access said object and users that are to be excluded from accessing said object. 
     
     
         3 . A method as recited in  claim 2  wherein said determining involves interpreting said access control policy is interpreted to determine users that are to be allowed read-only access to said object and determines users that are to be allowed read-and-write access to said object. 
     
     
         4 . A method as recited in  claim 3  wherein said determining involves distinguishing read and write access types and based on the expected relative frequency of read and write accesses; and setting said replication number such that an expected greater number of write accesses relative to the expected number of read accesses results is a relatively lower number of object replicas whilst a lower number of expected write accesses relative to a number of expected read accesses results in a relatively greater number of object replicas. 
     
     
         5 . A method as recited in  claim 1  wherein said storing involves storing said object in computer-readable media of multiple storage nodes. 
     
     
         6 . A method as recited in  claim 1  wherein said determining is also a partial function of accesses by said permitted users of other objects. 
     
     
         7 . A method as recited in  claim 2  further comprising:
 receiving requests for access to said object; and 
 applying said access controls so as to permit only permitted users to access said object. 
 
     
     
         8 . A method as recited in  claim 7  further comprising load balancing requests by permitted users so that different replicas of said object are accessed pursuant to different requests. 
     
     
         9 . A method as recited in  claim 8  further comprising:
 monitoring accesses of said object; 
 updating usage data for said object; and 
 adjusting the number of replicas of said object as a function of said usage data. 
 
     
     
         10 . A method as recited in  claim 9  further comprising using said usage data for said object in determining replication values for other objects. 
     
     
         11 . A system comprising computer-readable media encoded with code defining a replication controller that computes a replication number of replicas of an object to be stored at least in part as a function of access control policies. 
     
     
         12 . A system as recited in  claim 11  further comprising processors for executing said code. 
     
     
         13 . A system as recited in  claim 12  further comprising storage nodes for storing respective ones of said replicas. 
     
     
         14 . A system as recited in  claim 11  further comprising an access controller for controlling access to said object according to said access control policies. 
     
     
         15 . A system as recited in  claim 14  further comprising:
 a usage monitor for tracking accesses of said object; 
 a usage database for storing data generated by said usage monitor; and 
 a usage analyzer for analyzing said usage to provide statistical data for storage in said database. 
 
     
     
         16 . A system as recited in  claim 15  wherein said replication controller adjusts said replication value in part as a function of said statistical data. 
     
     
         17 . A system as recited in  claim 15  wherein said replication controller provides for computing replication values for subsequently stored objects at least in part as a function of said statistical data. 
     
     
         18 . A system as recited in  claim 13  further comprising a load balancer for distributing requests for said object among said nodes according to said access control policies. 
     
     
         19 . A system as recited in  claim 16  wherein said access control policies distinguish between users with write access and users with read-only access. 
     
     
         20 . A system as recited in  claim 19  wherein:
 said statistical data distinguishes read and write access types; and 
 based on the relative frequency of read and writes accesses, said replication controller sets said replication number such that a greater number of write accesses relative to a number of read accesses results in a relatively low replication number while whilst a lower number of write accesses relative to a number of read accesses results in a relatively greater replication number.